Signal for composite telegraphic and telephonic transmission.



No. 700,9. Patented May 27, :902'.

E. L. GRAUEL. SIGNAL FOR COMPOSITE TELEGRAPHIG AND TELEPHONIG TRANSMISSION.

(Application filed Jan. 24, 1902.)

(No Model.) 2 SheetsSheet I.

' Waawfor undo wAsumaToN o c No. 700,911. Patented Ma'y 27, I902.

- E. L. GRAUEL.

SIGNAL FOR COMPOSITE TELEGRAPI-IIO AND TELEPHONIO TRANSMISSION.

(Application filed Jan. 24, 1902.)

(No Model.) 2 Sheets-Shani 2.

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EDWVIN L. GRAUEL, OF CARTIIAGE, NEW YORK.

SIGNAL FOR COMPOSITE TELEGRAPHIC AND TELEPHONIC TRANSMISSION.

SPECIFICATION forming part of Letters Patent No. 700,911, dated May 27, 1902.

Application filed January 24,1902. Serial No. 91,099. (No model.)

To aZZ whom it may concern:

Be it known that I, EDWIN L. GRAUEL, a citizen of the United States, residing at Garthage, county of Jefferson, and State of New York, have invented certain new and useful Improvements in Signals for Composite Telegraphic and Telephonic Transmission; and I hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, in which- Figure 1 in the drawings shows a diagram of a system embodying my invention. Fig. 2 is a simplified diagram omitting details of stations and here inserted to make clearer the explanation of the method.

Like symbols refer to like parts wherever they occur.

My invention relates generally to the method known as composite transmission for simultaneously transmitting telephonic and telegraphic messages upon "the same circuit by the principle of superposed currents, but more specifically to the use of superposed currents for the purpose of producing a signal, and this I accomplish Without adding anything to or changing the regular Morse telegraph system or the working adjustment thereof,whatever the same may happen to be. Composite transmission by such devices as diiferentiate the telephonic and telegraphic currents is well known, and such system forms no part of my invention.

It is always desirable to have a special sig nal independent of the regular Morse signal or regular telephone-signal, which shall be available and sufficient, and especially is this the case in emergencies, as in railroad accidents, &c., where it often becomes necessary to communicate with the train despatchers office or other point immediately from a point between telegraph-stations, and in such cases if the superposed telephonic current is to be rendered available it is imperative that a positive and unfailing call be sent in to call attention thereto; but as at present practiced this can only be reliably accomplished by utilizing the regular Morse key and by cutting into the wire (a very undesirable thing to do under such circumstances) or by supplemen ting the usual Morse instruments with addi tional apparatus. Heretofore it has been nec essary either to employ the telegraph instruments themselves, using the regular telegraphic code, or special apparatus introduced in or supplemented on the circuit to notify the operators that the telephone is to be used. By my system it is not necessary to cut or loop into the line, nor is any special apparatus added to or supplemented on the Morse circuit at the stations in order to effect a sure and certain signal. All those devices which are cut or looped into the wire depend for their operation upon utilizing only the initial energy of the circuit; but as the adjustments of the relays, as well as the strength of battery maintained on telegraph-circuits, vary in almost every instance it is impractical to send a reliable calling-signal except by cut ting or looping into the wire, as before stated. It is evident that a method of signaling which is independent of such conditions is far more reliable than other methods heretofore employed. My method does not burden the Wires with individual telephone-signals for each station; but a general signal for telephone is sufficient, and my signal therefor can be sent on the telegraph-Wire from any point and in the desired direction without interfering with the working of the line, except between the signalingpoints. I accomplish this result by using the principle of polarity, a direct pulsating current of electricity being superposed on the ordinary Morse circuit, thereby strengthening the battery on that part of the line which is in direct polarity with the superposed signaling current, causing no action of the relays, but being in opposition to the force of linebattery on that part of the circuit which is in reverse polarity. All relays on such part of the circuit are caused to annunciate a pul sating call. Direct pulsatory, intermittent,or undulatory currents may be employed; but for the purposes of this specification all such currents are here comprised in the one term, direct pulsatory currents, the characteristic being that there are alternate periods of changed intensity of current and of such slow frequency as will enable it to operate the relays of the usual Morse circuit. This pulsating call being entirely distinct and different from the calls of the Morse circuit may be taken as a signal for telephone without being otherwise made definitive; but it will be at once evident to those skilled in the art that by adopting the Morse or other predetermined system of signals it will be possible to communicate at length from the signaling-station to the receiving-station to the exclusion of those not within the signalingcircuit.

By my method it is not necessary to be cut or looped into the line, a simple hooking, tapping on, or attaching to the wire su'fficing, the line-batteries not being used for eifectin g the signal. Further, by changing the polarity of the direct pulsating current I am enabled to call or signal in either direction on the linewire at will.

While I have chosen for the purposes of illustrating my invention to superpose the signaling-current upon a Morse circuit and employ a direct pulsating current for that purpose, yet it is to be understood that the fundamental principle is not confined in its application to such circuit or the use of such a current, but resides in this, that whatever the character of the superposed signalingcurrent it acts in conjunction or is compounded with the current on which it is superposed to produce the signal, thus enabling me to utilize the instruments ordinarily influenced to announce the signal. The currents of other apparatus employing superposed currents-as, for example, quadruplex telegraph systemsdo not actin conjunction or combination to influence the signal-announcing apparatus, but are independent of each other and do not depend on the existence of each other to produce the desired result.

To these ends the main features of my invention may be generally stated as follows: First, superposing upon an established current a current which acts in conjunction or combination therewith to effect a signal; second, superposing a direct pulsating current upon a current of fixed polarity; third, superposing a direct pulsating current upon a line-wire carrying a current of fixed polarity without impairing the integrity of the said line-wire, and, fourth, superposing a pulsating current of predetermined polarity upon a current of which the direction or polarity is fixed.

There are other minor features of invention, all as will hereinafter more fully appear.

Iwill now proceed to describe myinvention more fully, so that others skilled in the art to which it appertains may apply the same.

In Fig. 1 of the drawings, A is a telephonic transmitter; B, a telephonic receiver; 0, a spring-actuated hook-switch or switch-arm so arranged that upon removal of the re ceiver from its fork, hook, or holder the telephone is put in circuit and the pulsating current is out out, the pulsating circuit being also normally open at the generator L and at the break L the pulsating current being in an open circuit, which is automatically closed at the time the direct pulsating current is generated and the receiver is in its holder, the telephone being cut out when the receiver is in such position.

The break or circuit-closer L above referred to may be of any desired character; but I prefer to control it by a longitudinal advance of the generator-axle, which closes the break when the current is generated.

D is the local battery of the telephone-circuit.

E is an induction-coil,in the primary circuit of which is the telephone-transmitter A and in the secondary circuit of which is the telephone-receiver.

F is a condenser mediately interposed between the receiver and the line-wire, thus completing the induction-circuit,but preserving the line intact, so far as the Morse sig nals are concerned, by reason of the fact that the pulsating-current device stands normally open, even if the receiver be on or off its hook.

L is the source of the direct pulsating current, which may be of any well-known character-as, for example, a dynamo or voltaic batterybutis preferably a two-segment generator, as indicated on the diagram, one segment only being alive in order to decrease speed of pulsations, a circuit-closer L being interposed between the generator and the line in order to maintain the circuit normally open for the purposes hereinbefore set forth. One terminal of the armature-coil of said pulsating-current generator is connected to a contact-point ot' the hook-switch C, theother pole being connected to the spring-jacks J J, thus completing the circuit through one or the other of the spring-jacks when the plug P is inserted in either jack, the receiver B is in its holder, and the pulsating currentis being generated.

JJare spring-jackshavingleaf-springs a a, which are adapted to contact the tip a of the plug P when the latter is inserted in the spring-jackopeningsb'b. TheplugPiscomposed of two principal parts, the tip or interior part a and sleeve or exterior part b, which respectively contact the spring-jack at a and Z) when the plug is inserted. The interior a of the plug P is connected to the wire to be tapped or bridged on the Morse circuit, (in the present instance through the metallic axle e of reel Q, on which is spooled sufficient wire to reach the line-wire.) The exterior b of the plug P is grounded, as at G.

W Z illustrate one well-known arrangement for composite telephonic and telegraphic transmission; but it is to be understood that my invention applies to other systems and arrangements accomplishing the same purpose, and I do not intend to limit myself to the arrangement here shown.

MB MB are the line-batteries of the regular Morse circuit grounded at G G, the terminal stations being equipped with the usual keys, relays, Sounders, &c., and with'a con- I do denser between the phone and the Morse circuit. At each intermediate station M, MK is the Morse key, R the relay, S the sounder, and LB the local battery, all commonly known.

F is a condenser, which bridges the key K and the relay B when the receiver is on the hook. \Vhen the receiver is off the hook at the intermediate station, the telephone is bridged onto the line through the condenser F.

T is the ordinary telephone apparatus, consisting of transmitter, receiver, inductioncoil, battery, &c.

The circles M M M are intermediate or way stations, between which itis proposed to attach my signaling apparatus, and represent similar arrangements to that shown at the first intermediate station M.

It will be readily seen by tracing the currents through their connections that when the receiver B is in its holder and the plug P in sorted in one of the spring-jacks, a direct pulsating current being generated by any of the methods hereinbefore mentioned, said current will flow from L to the line-wire and that the relays which are in reverse polarity to that of the pulsating current by reason of the fixed direction of the line-batteries will annunciate a pulsating call, while those relays which are on that part of the line having the same polarity of current as the pulsating current-that is to say, relays having'the same polarity as that of the pulsating current-will be unaffected, as previously explained, and it is to be noted that because of the manner in which the spring-jacks are wired or connected with each other and with the source of the pulsating current a simple change of the plug P from one spring-jack to its companion operates to change the polarity of the pulsating current with respect to the fixed polarity of the Morse current, thus enabling me to signal in either direction on the line at will and without affecting telegraphic communication between stations outside of the signaling-points, as before explained; but any method of pole-changing may be employed.

Vhile I have herein shown an apparatus designed and adapted to carry out the invention here set forth, I do not herein claim the same or limit myself to the use thereof, as any other suitable means may be employed which will readily suggest itself to one skilled in the art.

Referring to the diagram Fig. 2, it will be noted that the points marked from g to g represent the ground or return section of the circuit, that W and Z indicate the terminal stations, while to and w indicate the intermediate stations of the line, the circle constituting a Morse circuit. L indicates a source of direct pulsating current grounded on one side and which may be connected at any point of the line-circuit between the terminal stations, as at 7L2. It will now be noted that if a direct pulsating current be generated at L and superposed upon the Morse circuit, as at W, said direct superposed pulsating current having the direction of the Morse circuit, as indicated by the arrow 2, the terminal battery at Z will be augmented, thereby not opening the relays on that part of the circuit, while the terminal battery at WV will be opposed, and thus affect the relays on such part of the circuit, a signal being thus produced on the latter relays, the other part of the circuit being unaffected for all purposes of the Morse system or for telephoning. By reversing the polarity (or direction) of the direct pulsating current I am enabled to interchange or reverse the conditions of the two parts of the circuit. Thus the signaling is effected by producing through the medium of opposing currents an unbalanced condition in one portion or branch of the multiple circuit into which the Morse or telegraphic circuit is temporarily converted, and such signaling is partially selective in that the other branch of the circuit is unaffected by the superposed and augmenting signaling-currents.

\Vhat I claim, and desire to secure by Letters Patent, is-

1. The method of transmitting intelligence which consists in imposing on a current of fixed direction an unidirectional pulsating current, thereby unbalancing the current of fixed direction in one half and reinforcing it on the other half of the circuit, substantially as specified.

2. The method herein described for signal ing which consists in superposin g upon a current, a current which compounds or acts in conjunction with the first-named current to effect a signal, substantially as specified.

3. The method herein described for signalin g which consists in superposing upon a current a current acting in opposition thereto, substantially as and for the purposes specified.

t. The method herein described for signaling on a current of fixed direction, the same consistingin superposing thereon a direct pulsating current of such slow frequency as will operate the line-relays, substantially as specifled.

5. The method herein described for signaling on a current of fixed direction, which consists in superposing thereon a direct pulsating current of opposite direction, substantially as and for the purpose specified.

6. The method herein described for signaling on a current of fixed direction, which consists in superposing thereon a direct pulsating current without impairing the integrity of the line-wire of the current of fixed direction, substantially as specified.

7. The method herein described for changing the direction of the signal, said signal being produced by super-posing a direct pulsatin g current upon a current of fixed direction, which consists in reversing or changing the direction of the direct pulsating current.

8. The method herein described for signal- 10. The method for signaling over a tele- 1 graphic circuit, which consists in directing over said circuit in multiple relation therewith, intermittently-transmitted direct currents of either polarity, and thereby unbalancing alternative portions of said circuit, substantially as specified.

In testimony whereof I affix my signature, in presence of two witnesses, this 22d day of January, 1902.

EDWIN L. GRAUEL.

Witnesses:

HUGH M. STERLING,- G. P. BITTER. 

